Empirical data on 220 families with de novo or inherited paracentric inversions
- Univ. of Tennessee College of Medicine, Chattanooga, TN (United States); and others
Six new cases of paracentric inversions (3 detected prenatally) are presented and added to an expanding database of paracentric inversions. Three inversions were associated with an abnormal phenotype and detected postnatally: inv(2)(p21p23), inv(13)(q14q34), and inv(18)(q12.3q23). The present database of paracentric inversions includes 220 families reported. All chromosomes were involved except chromosome 20. The most frequent inversions were found on chromosomes 1, 3, 7, 11, and 14. 48 index cases had an abnormal phenotype not explainable by other causes such as additional chromosome abnormalities. Of these, 12 were de novo and 36 familial. By contrast, of the 122 index cases with normal phenotype, there were 8 de novo and 87 familial cases (rest unknown). Ascertainment bias probably accounts for some of the abnormal inherited inversions cases. Maternally inherited inversions were more frequent than paternally inherited (72 versus 55). Inversions were found in males more than females (ratio of 4 to 3). There were some paracentric inversions that appear to be less involved with abnormal phenotypes (e.g., 11q21q23) than other inversions (e.g., inv X and Turner syndrome). An interesting observation which warrants further investigation is the excess number of fetal losses and karyotypically abnormal progeny in paracentric inversion carriers. The presence of additional karyotypic abnormalities in the children might be explainable by interchromosomal effects and chromosome position changes in the nucleus. Genetic counseling for paracentric inversions should take into consideration mode of ascertainment, inheritance, and chromosome involved. We solicit other cases of paracentric inversions to make this database more useful in counseling patients and families.
- OSTI ID:
- 133675
- Report Number(s):
- CONF-941009--
- Journal Information:
- American Journal of Human Genetics, Journal Name: American Journal of Human Genetics Journal Issue: Suppl.3 Vol. 55; ISSN AJHGAG; ISSN 0002-9297
- Country of Publication:
- United States
- Language:
- English
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